[en] The kinetics of the ozonolysis of unsaturated hydrocarbons in a flow-type barbotage reactor with the use of tetrachloromethane as the solvent is investigated. It is found that a side reaction of ozone with the solvent which has the first order with respect to ozone proceeds in the system. It follows from the comparison of the theoretical and experimental data that this reaction does not affect the measurement of the amount of ozone consumed for the ozonolysis of the specimen per se. It is concluded that the side reaction proceeds at a stage preceding the interaction of ozone with unsaturated hydrocarbons in the liquid phase of the reactor.

[en] In this paper we describe the creation of films from poly (glycolide-DL-lactide). Studied the mechanical properties of developed polymer films of poly (glycolide-DL-lactide). The effect of the molecular weight of poly (glycolide-DL-lactide) on the mechanical properties of the resulting polymer films is shown. The dependence of the mechanical properties of poly (glycolide-DL-lactide) films on the polymer concentration in chloroform was studied. The possibility of creating biodegradable films with specified mechanical properties is shown. (paper)

[en] This waste management plan establishes the requirements for the management and disposal of waste associated with the expedited response action for 200 West Area carbon tetrachloride plume and the 200-ZP-1 and 200-PW-1 Operable Units

[en] Highlights: • Line mixing of CH₃Cl-N₂ has been calculated from a potential including short range forces. • The semi-classical model takes into account the k-degeneracy of the transitions. • A new difficulty appears in the calculation when an atom-atom potential model is added. • A pragmatic method allows to by-pass that problem. • It leads to a good agreement with the available data. Line coupling and line mixing effects of CH₃Cl lines in the ν₁ band perturbed by N₂ have been investigated. We have taken into account the non-diagonality of the exp(−S₂) operator within specified line spaces as well as the k-degeneracy of the transitions (due to the double degeneracy of the j,k levels with k ≠ 0). These transitions should be considered as doublets coupled by the line mixing process. A new problem appears in the calculation when the atom-atom potential model is introduced. In order to overcome this difficulty, a pragmatic approach is proposed. Comparisons of theoretically calculated matrix elements of W with measurements of QR(j,k) doublets as well as some QQ_k sub-branches, which are strongly affected by line mixing, have been made. The results show that the formalism improved in this way leads to rather accurate predictions.

[en] We report a pump-probe femtosecond transient absorption spectroscopic study on the electron transfer reaction of CCl₄ in liquid ethanol. By direct observations of the presolvated electron and of the reaction transition state CCl₄*^-, this study provides direct evidence of the resonant dissociative electron transfer (RDET) of the presolvated electron to CCl₄. Moreover, the lifetime of CCl₄*^- in ethanol is directly obtained from the decay kinetics and its measured value is found to be nearly identical to its gas-phase value. Hence, these results also imply that RDET can be an efficient process in an aqueous environment

[en] Effective design of in situ remediation technologies often requires an understanding of the mass transfer limitations that control the removal of contaminants from the soil. In addition, the presence of nonaqueous phase liquids (NAPLs) in soils will affect the ultimate success or failure of remediation processes. Knowing the location of NAPLs within the subsurface is critical to designing the most effective remediation approach. This work focuses on demonstrating that gas tracers can detect the location of the NAPLs in the subsurface and elucidating the mass transfer limitations associated with the removal of contaminants from soils

[en] This paper introduces a parametric study of nanofiber fabrication. Poly-Caprolactone(PCL) and Chloroform are basic material for nanofiber fabrication with electrospinning method. The device for electrospinning was composed of a syringe pump, syringe, high voltage generator and 32gauge plastic nozzle. PCL concentration, applied voltage, solution flow rate and the tip to collector distance (TCD) were parameters in electrospinning method. As a result of electrospinning experiment, it was found that as TCD and applied voltage increased, the diameter of fibres was decreased. In feed rate experiment, the size of fibres decreased when feed rate decreased. The optimized PCL concentration was found at 6w/v% for the minimum of fibres. (paper)

[en] Phase transitions of a 225-molecule cluster of carbon tetrachloride have been studied by a molecular dynamics simulation. A five-site model potential function was developed to reproduce the density and heat of vaporization of the bulk liquid. Computations began with orientationally disordered molecules distributed in fcc lattice sites of a nearly spherical cluster. The cluster was heated from a low temperature to 200 K in 10-deg steps of 50 ps each and then cooled to 10 K. Translational and rotational transitions were monitored by following several indicators including the translational and rotational diffusion and rotational entropies of individual molecules. Melting began at the surface and propagated inward as the temperature increased. Solidification of the molten cluster proceeded from the center to the surface. At the high cooling rate of the simulation, however, molecules were unable to organize into a crystalline array and solidified into a glassy structure instead. Except for spatial order, the indicators of degree of liquefaction exhibited almost the same temperature dependence in the crystsl → liquid as in the liquid → glass transition, a behavior that could be rationalized on the basis of Lindemann's theory of melting. Results were compared with predictions of an illustrative model due to Reiss, Mirabel, and Whetten. Qualitatively, the model included all of the features of the simulation. Quantitatively, the model grossly underestimated the range over which the melting transition took place. 40 refs., 10 figs., 1 tab

[en] The kinetics of thermal anomalies at the phase transitions in the tetraethylammonium zinc tetrachloride crystal [N(C₂H₅)₄]₂ZnCl₄ has been studied by the differential scanning calorimetry method over a wide range of rate of temperature change, from 1 to 100 K min^-1. The crystal is known to undergo structural phase transitions of first order at which the nucleus of the final phase characterized by a symmetry different to that of the initial phase appears and develops. The classical Johnson-Mehl-Avrami model cannot be applied to describe the two phase transitions taking place in the non-isothermal process. Making use of the isothermal process taking place below T₁^C, the intermediate phase has been shown to be metastable; the energy of the process is E_a = 146 ± 7 kJ mol^-1, while the Avrami exponent n = 2.3 ± 0.2

[en] Crude chloroform purification methods to remove impurities with properties similar to those of chloroform (1,1-dichloroethane and cis-1,2-dichloroethylene) were analyzed. The considered methods for removing impurities from crude chloroform included reaction-rectification and separate processing in a reactor and a distillation column. The results of simulation of the above schemes are presented. Comparative analysis of the results taking into consideration economic viability showed that purification of crude chloroform by reaction-rectification shows great promise.